Wind turbines have gained increased acceptance as an environmentally safe and relatively inexpensive alternative energy source. With this growing interest, considerable efforts have been made to develop wind turbines that are more reliable, efficient, and easier to maintain.
Generally, a wind turbine includes a rotor having one or more blades. The rotor is mounted on a housing or nacelle, which is positioned on top of a truss or tubular tower. The turbine's blades transform wind energy into a rotational torque or force that drives one or more generators that are rotationally coupled to the rotor through a gearbox. The gearbox steps up the inherently low rotational speed of the turbine rotor for the generator to efficiently convert mechanical energy to electrical energy, which is fed into a utility grid. Gearless direct drive turbines also exist.
It is often necessary to mount certain components to the internal structure of the rotor blades. For example, wind turbines operating in cold climates are typically equipped with a deicing capability, wherein deicing components such as a fan, heater unit and power/control cabinets are mounted to the internal shear webs. It is also a typical practice to mount lighting strike components (e.g., cables, and the like) to the shear webs or other internal structure.
A problem, however, with conventional techniques used to mount the various components to shear webs or other internal structure is that damage often occurs to the sandwich construction of the web, which is typically a foam core between biax laminate panels. When bolts are passed through the webs, the substantial compressive load on the bolts is transferred through the biax laminates to the foam core, tending to crush the foam material and also cause premature delamination of the biax laminate panels. Although it has been attempted to reinforce the mounting location with additional layers of fiberglass, this has not proved successful in preventing collapse of the foam material at the mounting location.
The present invention provides an improved method and system for mounting components to sandwich-type web structures within a wind turbine rotor blade that addresses at least certain of the issues noted above.